Morphometric analysis of the proximal thoracic pedicles in Lenke II and IV adolescent idiopathic scoliosis: an evaluation of the feasibility for pedicle screw insertion

PURPOSE

Pedicles on the concave side of the proximal thoracic (PT) curve in adolescent idiopathic scoliosis (AIS) patients with Lenke II and IV deformities tend to be narrow and dysplastic, making pedicle screw (PS) insertion challenging. The aim of this study was to evaluate the feasibility for PS placement in these patients using pedicle chord length, diameter, and channel morphology.

METHODS

In this retrospective study, 56 consecutive AIS patients with Lenke II or IV curves who underwent instrumented posterior spinal fusion (PSF) were studied. The mean age at surgery was 14.8 years and the mean PT curve measured 45°. Two independent investigators evaluated all visible pedicles from T₁ to T₆ vertebral levels using axial images from intraoperative computed tomography-guided navigation recording the pedicle: (1) maximum transverse diameter 'd' at the isthmus, (2) maximum chord length 'l', and (3) qualitative assessment of the channel morphology (types A-D).

RESULTS

Two hundred and sixty-eight concave and 264 convex pedicles were measured. The mean 'd' of the concave pedicles at T₃ and T₄ was < 3.0 mm, compared to > 5.0 mm for the convex counterparts (p < 0.001). Of all concave pedicle channels, 48% had morphology characteristics that were riskier for PS cannulation (type C or D) compared to 2% of all convex pedicle channels (type A or B) (p < 0.001).

CONCLUSION

Almost half of all concave pedicles have morphologic characteristics that make them too small to accommodate a PS. Though PSs could be inserted using an in-out-in technique in these patients, alternative fixation anchors may improve strength and safety.

Risk of Scoliosis Progression in Nonoperatively Treated Adolescent Idiopathic Scoliosis Based on Skeletal Maturity

BACKGROUND

Hand radiographs for skeletal maturity staging are now frequently used to evaluate remaining growth potential for patients with adolescent idiopathic scoliosis (AIS). Our objective was to create a model predicting a patient's risk of curve progression based on modern treatment standards.

METHODS

We retrospectively reviewed all AIS patients presenting with a major curve <50 degrees, available hand radiographs, and complete follow up through skeletal maturity at our institution over a 3-year period. Patients with growth remaining underwent rigid bracing of curves >25 degrees, whereas patients between 10 and 25 degrees were observed. Treatment success was defined as reaching skeletal maturity with a major curve <50 degrees. Four risk categories were identified based on likelihood of curve progression.

RESULTS

Of 609 AIS patients (75.4% female) presenting with curves over 10 degrees and reaching skeletal maturity at most recent follow up, 503 (82.6%) had major thoracic curves. 16.3% (82/503) of thoracic curves progressed into surgical treatment range. The highest risk group (Sanders 1 to 6 and curve 40 to 49 degrees, Sanders 1 to 2 and curve 30 to 39) demonstrate a 30% success rate with nonoperative treatment. This constitutes an 111.1 times (95% confidence interval: 47.6 to 250.0, P<0.001) higher risk of progression to surgical range than patients in the lowest risk categories (Sanders 1 to 8 and curve 10 to 19 degrees, Sanders 3 to 8 and curve 20 to 29 degrees, Sanders 5 to 8 and curve 30 to 39 degrees).

CONCLUSIONS

Skeletal maturity and curve magnitude have strong predictive value for future curve progression. The results presented here represent a valuable resource for orthopaedic providers regarding a patient's risk of progression and ultimate surgical risk.

LEVEL OF EVIDENCE

Level III-retrospective cohort study.

Outcomes and Complications in Management of Congenital Myopathy Early-Onset Scoliosis

BACKGROUND

Congenital myopathies (CMs) are complex conditions often associated with early-onset scoliosis (EOS). The purpose of this study was to investigate radiographic outcomes in CM patients undergoing EOS instrumentation as well as complications. Secondarily, we sought to compare these patients to a population with higher prevalence, cerebral palsy (CP) EOS patients.

METHODS

This is a retrospective study of a prospectively collected multicenter registry. The registry was queried for EOS patients with growth-sparing instrumentation (vertical expandable prosthetic titanium ribs, magnetically controlled growing rods, traditional growing rod, or Shilla) and a CM or CP diagnosis with minimum 2 years follow-up. Outcomes included major curve magnitude, T1-S1 height, kyphosis, and complications.

RESULTS

Sixteen patients with CM were included. Six (37.5%) children with CM experienced 11 complications by 2 years. Mean major curve magnitude for CM patients was improved postoperatively and maintained at 2 years (P<0.01), with no significant increase in T1-S1 height or maximum kyphosis(P>0.05). Ninety-seven patients with CP EOS were included as a comparative cohort. Fewer CP patients required baseline respiratory support compared with CM patients (20.0% vs. 92.9%, P<0.01). Fifty-four (55.7%) CP patients experienced a total of 105 complications at 2 years. There was no evidence that the risk of complication or radiographic outcomes differs between cohorts at 2 years, though CP EOS patients experienced significant improvement in all measurements at 2 years.

CONCLUSIONS

EOS CM children face a high risk of complication after growing instrumentation, with similar curve correction and risk of complication to CP patients.

LEVEL OF EVIDENCE

Level III.

Rib-based Distraction Device Implantation Before Age 3 Associated With Higher Unplanned Rate of Return to the Operating Room

BACKGROUND

Surgical treatment of early-onset scoliosis (EOS) with rib-based implants such as the vertical expandable prosthetic titanium rib (VEPTR) is associated with a high rate of complications including surgical site infection, skin breakdown, and implant migration. Many of these complications warrant the need for unplanned reoperations, increasing the burden on an already vulnerable patient population, and introducing the further risk of infection. To provide insight into the risks of early intervention, we investigate the relationship between initial device implantation before the age of 3 and the rate of unplanned reoperation.

METHODS

A retrospective review was performed of all patients at a single institution who had undergone VEPTR insertion for EOS with at least a 2-year follow-up from 2007 to 2016. Patients were stratified into the case-cohort (0 to 2 y of age) or the comparison cohort (3 to 10 y of age) based on age at the time of device implantation. Multivariate regression accounting for age and scoliosis etiology was performed to identify factors predictive of unplanned reoperation.

RESULTS

A total of 137 of 185 patients treated with VEPTR were identified with 76 (56%) undergoing at least 1 unplanned reoperation during the study time period. There were 68 and 69 patients in the age 0- to 2-year and 3- to 10-year cohorts, respectively. Patients aged 0 to 2 years underwent a higher number of total procedures compared with those aged 3 to 10 (13.1±6.5 vs. 10.6±4.8, P=0.032). A significant difference was found in the rate of unplanned reoperation between the 2 cohorts with 44 (65%) patients aged 0 to 2 and 32 (46%) patients aged 3 to 10 undergoing at least 1 unplanned reoperation (P=0.031). Binary logistic multivariate regression accounting for age and scoliosis etiology demonstrated that patients aged 0 to 2 had a significantly greater odds of undergoing an unplanned reoperation (odds ratio=3.050; 95% confidence interval: 1.285-7.241; P=0.011) compared with patients aged 3 to 10 years.

CONCLUSION

Overall, EOS patients aged 0 to 2 at initial VEPTR implantation are up to 3 times higher risk of undergoing an unplanned reoperation compared with those aged 3 to 10.

LEVEL OF EVIDENCE

Level III.

Could have tethered: predicting the proportion of scoliosis patients most appropriate for thoracic anterior spinal tethering

BACKGROUND

Posterior spinal fusion (PSF) has proven to be a safe, reliable technique to treat spinal deformities in adolescents. In recent early reports, vertebral body tethering (VBT) is showing promise as a method to modulate growth, driving scoliosis correction, while offering the potential added benefit of maintaining some flexibility in the instrumented segment. With recent FDA humanitarian device exemption (HDE) approval, VBT is poised to become more widely available as a treatment for a subset of current PSF candidates. Our aim was to use approved criteria from a recent FDA IDE to determine who could have been tethered in the years preceding approval.

METHODS

A retrospective analysis was performed of patients with idiopathic scoliosis treated with PSF or VBT at a large pediatric spine center from 1/1/2016 to 6/25/2019. Tethering indications followed the criteria outlined by an ongoing FDA IDE: age 8-16, Sanders bone age ≤ 4, primary thoracic curve between 35° and 60°, and lumbar curve < 35°. Risser sign and triradiate cartilage status were also employed to ascertain skeletal maturity in the absence of Sanders score.

RESULTS

Of the 359 patients (78.6% female) who underwent PSF or VBT for idiopathic scoliosis, 75 (20.9%) met IDE criteria for VBT (57 had PSF and 18 had VBT). 284 were not appropriate for thoracic VBT: 77 (21.4%) had a non-thoracic primary curve, 80 (22.3%) were too mature at presentation, 36 (10.0%) had a lumbar curve > 34°, 9 (2.5%) had a main thoracic curve out of range, and 1 had a proximal thoracic curve > 40°. 81 patients (22.6%) had multiple exclusionary criteria.

CONCLUSIONS

After decades with a successful treatment for AIS (PSF), we are at an inflection point: VBT is conditionally approved by the FDA as an HDE device, unleashing more widespread use. Many pediatric spine surgeons will want to know what proportion of PSFs will someday be VBTs. If FDA IDE criteria are used to ensure that a VBT candidate has an appropriate maturity stage and scoliosis deformity pattern, 20.9% of our 359 surgical range patients would have qualified for thoracic VBT.

LEVEL OF EVIDENCE

Level III.

A seat at the table: an invitation to the SRS podium via the study group

PURPOSE

The SRS annual meeting (SRS-AM) represents the pinnacle of research in the field of spinal deformity. Spine surgery research was historically based on single-surgeon experience, but an increasing number of abstracts presented at SRS-AM are conducted by multicenter study groups, which may have improved the quality of literature available to surgeons. We sought to determine the proportion of SRS-AM podium presentations (PP) resulting from study groups over a 15-year period.

METHODS

1874 PP from the 2005-2019 SRS-AM were reviewed to determine if they resulted from a study group or multicenter collaboration. Abstracts were also classified as pediatric- or adult-focused. Pearson correlations were calculated to analyze changes in the proportion of study group or multicenter PP.

RESULTS

The number of SRS PP increased from 102 to 171 from 2005 to 2019. 381 (20.3%) PP were identified as a study group product, while 536 (28.6%) resulted from multicenter collaboration. The proportion of study group PP increased by 0.9% annually from 8.8 to 26.9% (r² = 0.44, p = 0.007), while multicenter PP increased by 1.2% annually from 11.8 to 40.9% (r² = 0.51, p = 0.003). A greater proportion of study group PP were level of evidence I or II studies compared to those not resulting from the work of study groups (53.8 vs 19.3%, p < 0.001).

CONCLUSION

SRS-AM PP resulting from research study groups and multicenter collaborations increased over threefold from 2005 to 2019. Spine surgeons are taking a more proactive approach to produce more generalizable research with higher level of evidence through multicenter study groups, allowing them to make more informed decisions to ultimately improve surgical outcomes for patients.

LEVEL OF EVIDENCE

V.

Complications, Reoperations, and Mid-Term Outcomes Following Anterior Vertebral Body Tethering Versus Posterior Spinal Fusion: A Meta-Analysis

Background

Anterior vertebral body tethering (AVBT) is a growth-modulation technique theorized to correct adolescent idiopathic scoliosis (AIS) without the postoperative stiffness imposed by posterior spinal fusion. However, data are limited to small series examining short-term outcomes. To assess AVBT's potential as a viable alternative to posterior spinal fusion (PSF), a comprehensive comparison is warranted. The purpose of this meta-analysis was to compare postoperative outcomes between patients with AIS undergoing PSF and AVBT. Our primary objective was to compare complication and reoperation rates at available follow-up times. Secondary objectives included comparing mid-term Scoliosis Research Society (SRS)-22 scores, and coronal and sagittal-plane Cobb angle corrections.

Methods

We performed a systematic review of outcome studies following AVBT and/or PSF procedures. The inclusion criteria included the following: AVBT and/or PSF procedures; Lenke 1 or 2 curves; an age of 10 to 18 years for >90% of the patient population; <10% non-AIS scoliosis etiology; and follow-up of ≥1 year. A single-arm, random-effects meta-analysis was performed. Deformity corrections, complication and reoperation rates, and postoperative SRS-22 scores were recorded.

Results

Ten AVBT studies (211 patients) and 14 PSF studies (1,069 patients) were included. The mean follow-up durations were similar for both groups. Pooled complication rates were 26% for AVBT versus 2% for PSF, and reoperation rates were 14.1% for AVBT versus 0.6% for PSF with nonoverlapping confidence intervals (CIs). The pooled reoperation rate among studies with follow-up times of ≥36 months was 24.7% in AVBT versus 1.8% in PSF. Deformity correction, clinical outcomes, and mid-term SRS-22 scores were similar.

Conclusions

Our study showed greater rates of complications and reoperations with AVBT compared with PSF. Reoperation rates were significantly greater in AVBT studies with longer follow-up (≥36 months). Deformity correction, clinical outcomes, and mid-term SRS-22 scores were similar. While a potential fusionless treatment for AIS merits excitement, clinicians should consider AVBT with caution. Future long-term randomized prospective studies are needed.

Level of Evidence

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Scoliosis in Friedreich's ataxia: longitudinal characterization in a large heterogeneous cohort

OBJECTIVE

The objective of this study was to characterize the incidence and progression of scoliosis in the natural history of Friedreich's ataxia (FRDA) and document the factors leading to the requirement for corrective surgery.

METHODS

Data on the prevalence of scoliosis and scoliosis surgery from up to 17 years of follow-up collected during a large natural history study in FRDA (1116 patients at 4928 visits) were summarized descriptively and subjected to time to event analyses.

RESULTS

Well over 90% of early or typical FRDA patients (as determined by age of onset) developed intermediate to severe scoliosis, while patients with a later onset (>14 years) had no or much lower prevalence of scoliosis. Diagnosis of scoliosis occurs during the onset of ataxia and in rare cases even prior to that. Major progression follows throughout the growth phase and puberty, leading to the need for surgical intervention in more than 50% of individuals in the most severe subgroup. The youngest patients appear to delay surgery until the end of the growth period, leading to further progression before surgical intervention. Age of onset of FRDA before or after reaching 15 years sharply separated severe and relatively mild incidence and progression of scoliosis.

INTERPRETATION

Scoliosis is an important comorbidity of FRDA. Our comprehensive documentation of scoliosis progression in this natural history study provides a baseline for comparison as novel treatments become available.

Sinister! The high pre-op left shoulder is less likely to be radiographically balanced at 2 years post-op

PURPOSE

AIS patients consider shoulder balance an important cosmetic outcome after surgery. We examined the impact of preoperative left shoulder elevation (LSE) and choice of upper instrumented vertebra (UIV) on postoperative shoulder imbalance (PostSI).

METHODS

This was a retrospective cohort study utilizing a prospective AIS database. Patients had Lenke type 1-4 curves and preoperative shoulder height ≥ 1.0 cm. Patients with preoperative LSE and right shoulder elevation (RSE) were compared. Shoulder height difference < 1 cm was considered 'mild', 1-2 cm was 'moderate', and ≥ 2.0 cm was 'severe'.

RESULTS

407 patients had ≥ 1.0 cm imbalance preoperatively, with 88 (21.6%) LSE. There were no differences in gender (p = 0.855) or age (p = 0.477). Patients with LSE more frequently had Lenke type 2 curves (43.2% vs 16.3%, p < 0.001), while preoperative RSE averaged 1.9 ± 0.9 cm versus 1.6 ± 0.5 cm for LSE (p < 0.001). Those with LSE more often had severe PostSI at 2 years (30.7% vs 5.0%, p < 0.001), and only 26.1% of patients with severe preoperative LSE corrected to mild. In contrast, most patients with RSE had mild PostSI regardless of initial imbalance. When examining only LSE patients, there was no difference in preoperative SH by final UIV (p = 0.101). Further, UIV choice did not impact the proportion of severely unbalanced patients postoperatively (p = 0.446). A PTC > 34.5° was predictive of PostSI ≥ 2.0 cm for patients with preoperative LSE.

CONCLUSION

AIS patients with preoperative LSE are less likely to achieve level shoulders postoperatively. Choice of higher UIV did not affect postoperative shoulder imbalance in this cohort. A PTC > 34.5° was predictive of severe PostSI in patients with preoperative LSE.

LEVEL OF EVIDENCE

II.

Do Year-Out Programs Make Medical Students More Competitive Candidates for Orthopedic Surgery Residencies?

OBJECTIVE

As orthopedic surgery residency programs are becoming more competitive, medical students interested in orthopedics are increasingly completing "year-out" programs. This study sought to evaluate student and faculty perceptions of these programs.

DESIGN

A survey evaluating baseline characteristics was disseminated to directors of year-out programs identified through postings on the orthopedics forum, Orthogate.org. A second survey was sent to all program directors (PDs) of accredited US orthopedic residencies, while a final survey was distributed to participants identified by year-out PDs.

SETTING

Ninety-six orthopedic year-out programs at 56 institutions were contacted.

PARTICIPANTS

Twenty-six year-out programs, 72 PDs of ACGME-accredited orthopedic residencies, and 34 year-out participants from 6 programs completed our questionnaires.

RESULTS

73.1% (19) year-out program provided funding to participants, averaging $30,368. 84.6% (22) reported >75% match rates into orthopedics for participants. 65.4% (17) of programs selected students between their MS3/MS4 school years. 4.2% (3) of residency PDs agreed or strongly agreed that year-out programs were important factors for consideration in residency programs, compared with 82.4% (28) of year-out participants and 69.2% (18) of year-out PDs (p < 0.001). 58.8% (2) of year-out participants cited completion of a year-out for improving the chance of matching into any orthopedic residency, while 85.3% (29) wanted to be more competitive for top programs. The average Step 1 score was 248, which was insignificantly different from the national average for matched orthopedic applicants.

CONCLUSIONS

Orthopedic year-out programs have dramatically increased in number over the last 20 years. Most of these programs are funded, 1-year clinical research fellowships with relative match success for participants pursuing orthopedic residencies. While year-out PDs and students consider participation in such programs to be an important factor for residency applications, and often participate in them in order to improve their competitiveness for matching at desired programs, residency PDs overall hold different views.

Risk Factors for Reoperation Following Final Fusion After the Treatment of Early-Onset Scoliosis with Traditional Growing Rods

BACKGROUND

Although there is a high rate of reoperation after final fusion following the treatment of early-onset scoliosis with use of traditional growing rods, the risk factors for reoperation are unknown. The purpose of the present study was to identify risk factors associated with the need for reoperation after final fusion for the treatment of early-onset scoliosis.

METHODS

A multicenter database for patients with early-onset scoliosis was retrospectively analyzed. Patients managed with traditional growing rods and final fusion were identified (n = 248). The inclusion criteria were ≥1 lengthening procedure with traditional growing rods and ≥2 years of follow-up after final fusion or revision surgery within 2 years after final fusion (167 patients; 67%). Patients requiring reoperation following final fusion were compared with patients who did not require reoperation. The data that were analyzed included demographic characteristics, comorbidities, spinal deformity characteristics, radiographic measurements, perioperative details, and complications during all stages of treatment. A multivariate regression model was used to identify independent risk factors.

RESULTS

The mean duration of follow-up from the initial visit to the latest visit was 10.7 ± 4.1 years, and the mean duration of follow-up after final fusion was 4.9 ± 3.1 years. Thirty-two (19%) of the 167 patients required reoperation following final fusion. Curve progression requiring revision surgery during lengthening with traditional growing rods (adjusted odds ratio [aOR], 21.137 per event; p = 0.028), the number of levels spanned with traditional growing rods (aOR, 1.378 per level; p = 0.007), and the duration of treatment with traditional growing rods (aOR, 1.220 per year; p = 0.035) were independently associated with revision surgery after final fusion.

CONCLUSIONS

Independent risk factors for curve progression requiring reoperation during lengthening with traditional growing rods that require operative intervention include increasing number of levels spanned with traditional growing rods and longer duration of treatment with traditional growing rods. These findings may help with patient counseling and potentially guide surgeon decision-making.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Awake serial body casting for the management of infantile idiopathic scoliosis: is general anesthesia necessary?

STUDY DESIGN

It is a retrospective cohort study.

OBJECTIVES

To compare the radiographic and clinical outcomes of serial body casting for infantile idiopathic scoliosis (IIS) with versus without the use of general anesthesia (GA). Serial body casting for IIS has traditionally been performed under GA. However, reports of neurotoxic effects of anesthetics in young children have prompted physicians to consider instead performing these procedures while patients are awake and distracted by electronic devices.

METHODS

Patients from a multicenter registry who underwent serial casting for IIS were included. The patients were divided into asleep (GA) and awake (no GA) cohorts. Comparisons were made between pre-casting, first in-cast, and post-casting radiographic measures in each cohort. The rates of successful casting (≥ 10° major CA improvement), curve progression, and incidence of casting abandonment for surgical intervention were also compared.

RESULTS

One-hundred and twenty-one patients who underwent serial casting for IIS were included. Ninety-two (76%) patients were asleep during casting procedures, while 29 (24%) were awake. Patients in the awake cohort were older (p < 0.01), had a lower BMI (p = 0.03), and more severe curve magnitudes (p < 0.01) at baseline. Patients in the awake cohort experienced greater first-in-cast correction of the major curve (p = 0.01) and improvement in thoracic spine height (p < 0.01). The rate of casting success was higher in the awake cohort (72%) as compared to the asleep cohort (48%) (p = 0.02), although the rate of curve progression (worsening) was similar (p = 0.880). Lastly, there was a lower rate of conversion to surgery at 2 years post-initiation of casting, although this was not statistically significant (0% vs. 8%; p = 0.126).

CONCLUSIONS

Patients who underwent awake serial casting had similar radiographic outcomes as compared to those who were under general anesthesia during the procedures. Thus, awake casting may provide a safe and effective alternative to the use of general anesthesia in patients with idiopathic infantile scoliosis.

LEVEL OF EVIDENCE

III.

Correlation between surgical site infection and classification of early onset scoliosis (C-EOS) in patients managed by rib-based distraction instrumentation

OBJECTIVES

The aim of this study is to determine risk factors for infection among EOS patients treated by rib-based distraction instrumentation, and to further assess the incidence of infection among C-EOS categories and sub-types. Despite the heterogonous nature of early onset scoliosis, the classification of early onset scoliosis (C-EOS) has proven to have excellent reliability across its major categories. C-EOS's reliability has been verified; however, little data exist on the utility of this categorization in clinical decision-making and risk assessment.

METHODS

After institutional review board approval, data for EOS patients treated by rib-based distraction instrumentation were collected between 2013 and 2017 in a single institution. Data collection included: major categories of early onset scoliosis classification (etiology, major curve and kyphosis), BMI, height, weight, procedure type, site of procedure, presence of tracheostomy, and bowel/urinary incontinence.

RESULTS

156 EOS patients underwent 843 rib-based distraction instrumentation procedures. 22.4% of patients (35/156 patients, 42 procedures) developed infections, 30/35 requiring irrigation and debridement. Type of procedure was significantly associated with infection rate, with rib-based distraction instrumentation insertion corresponding with the highest incidence of infection, as compared to instrumentation revisions or expansions (p = 0.006). Infection rates were also more common in shorter and lighter weight children (p = 0.001 and 0.03; respectively). Patients with a neuromuscular etiology had the highest rate of infection in comparison to congenital, syndromic, and idiopathic (5.7% vs, 4.9%, 4.7%, and 2.6%; respectively). Notably, high infection rates occurred neuromuscular hyper-kyphotic subjects (M+), occurring in all major curve C-EOS subgroups and at a rate of 8.3% for all procedures.

CONCLUSION

Neuromuscular, larger magnitude major curve, and larger magnitude kyphotic angle C-EOS categories appear to be at a higher risk of infection. Such information potentiates the usefulness of C-EOS in surgical decision-making and in the informed consent process.

LEVEL OF EVIDENCE

Level III therapeutic.

The American Board of Orthopaedic Surgery Response to COVID-19

The COVID-19 pandemic has disrupted every aspect of society in a way never previously experienced by our nation's orthopaedic surgeons. In response to the challenges the American Board of Orthopaedic Surgery has taken steps to adapt our Board Certification and Continuous Certification processes. These changes were made to provide flexibility for as many Candidates and Diplomates as possible to participate while maintaining our high standards. The American Board of Orthopaedic Surgery is first and foremost committed to the safety and well-being of our patients, physicians, and families while striving to remain responsive to the changing circumstances affecting our Candidates and Diplomates.

Fusions ending at the thoracolumbar junction in adolescent idiopathic scoliosis: comparison of lower instrumented vertebrae

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To compare clinical outcomes and radiographic parameters between patients treated with a posterior spinal fusion that had a lower instrumented vertebra at T11, T12, and L1.

BACKGROUND

Posterior instrumented fusions are well established for treating patients with adolescent idiopathic scoliosis (AIS). Fusions limited to the thoracic spine can adequately correct a spinal deformity while preserving lumbar segmental mobility. However, fusions that end at the thoracolumbar junction have been proposed to cause adjacent segment complications. Studies comparing outcomes between patients who were treated with fusions that end at the thoracolumbar junction with varying LIVs are limited.

METHODS

A multicenter database was queried for patients with AIS that had Lenke Type 1 and 2 curves treated with a fusion that had an LIV at T11, T12, or L1. Coronal curve magnitude, degree of junctional kyphosis, C7-central sacral line, thoracic apical translation, and sagittal stable vertebrae were measured. Clinical and functional outcomes were assessed using the Scoliosis Research Society-22 (SRS-22) questionnaire and lumbar flexibility testing.

RESULTS

The lower instrumented level was below the sagittal stable vertebrae in 22.7%, 40%, and 66.2% of patients in the LIV-T11, T12, and L1 groups, respectively (p < 0.001). The 5-year postoperative lumbar curve magnitudes were 20.3°, 16.3°, and 14.0° for T11, T12, and L1-LIV, respectively (p < 0.001). No patients in the T11 group (0%), two patients in the T12 group (2.5%), and one patient in the L1 (0.8%) group developed distal junctional kyphosis (p = 0.5). The 5-year postoperative total SRS-22 scores were 4.21, 4.50, and 4.38 (p = 0.029). Lumbar flexion decreased by 0.78 cm in the T11-LIV group, increased by 0.01 cm in the T12-LIV group, and decreased by 0.15 cm in the L1-LIV group (p = 0.434).

CONCLUSION

There was no significant difference in SRS-22 scores, development of distal junctional kyphosis or loss of lumbar mobility between patients treated with a spinal fusion that had an LIV at T11, T12, or L1.

LEVEL OF EVIDENCE

Level III.

Unplanned return to OR (UPROR) for children with early onset scoliosis (EOS): a comprehensive evaluation of all diagnoses and instrumentation strategies

STUDY DESIGN

Retrospective analysis of a prospectively collected multicenter database.

OBJECTIVES

Our goal was to study unplanned return to the OR (UPROR, a postoperative complication that could not be treated without an additional anesthetic) as a function of C-EOS diagnosis and implant type. Growing concerns over the impact of multiple anesthetic events on the young brain have focused attention on limiting UPROR in early onset scoliosis (EOS).

METHODS

We studied all patients with a diagnosis of EOS who had surgical implantation of growing instrumentation from October 4, 2010, to September 27, 2015, with a minimum 2-year follow-up. Among the complications requiring surgical treatment (revision for implant or anchor failure, infection, or implant removal), we analyzed all UPROR events-those that required a separate anesthetic (could not be treated as part of a planned surgical lengthening) within the first 2 years after initial implantation. UPROR was analyzed by diagnosis, deformity type, and implant strategy using the C-EOS classification.

RESULTS

A total of 369 patients met inclusion criteria. Eighty-five of the 369 (23%) required unplanned trips to the operating room for various reasons. The C-EOS group at highest risk of an unplanned trip to the operating room is the hyperkyphotic neuromuscular (M3+, 14/85) cohort, followed closely by the congenital (C3N, 9/85) and neuromuscular (M3N, 8/85) groups with normal sagittal profiles and Cobb angles between 50° and 90°. Implant strategy was significantly related to risk of UPROR (p = .009; Table 1), with traditional implants (vertically expandable prosthetic titanium rib/traditional growing rod) being less likely to have an UPROR event.

CONCLUSIONS

Growing instrumentation to treat EOS, when considered comprehensively, results in a true unplanned reoperation rate within 2 years of implantation of 23% (85/369). UPROR events are more common with certain C-EOS groups (hyperkyphotic neuromuscular deformities) and implant strategies. Families should be counseled that unplanned anesthetics are common with any implant strategy available today.

LEVEL OF EVIDENCE

Level III, therapeutic.

Pediatric ACL Reconstruction and Return to the Operating Room: Revision Is Less Than Half of the Story

BACKGROUND

Although there are several causes of unplanned return to the operating room (RTOR) following pediatric anterior cruciate ligament (ACL) reconstruction (ACLR), prior outcomes studies focus primarily on the risk of graft failure. We sought to comprehensively describe indications for RTOR in pediatric primary ACLR patients, estimate associated rates of RTOR, and assess the impact of concomitant meniscal procedures on these rates.

METHODS

This retrospective cohort study considered patients who underwent primary ACLR at an urban, pediatric tertiary care hospital between 2013 and 2015. Cohorts were defined based on the presence or absence of a concomitant surgical meniscal procedure with the index ACLR. The primary outcome was RTOR for an indication pertaining to ACLR or a potential predilection for knee injury. Cases of RTOR were cataloged and classified according to indication. Survival analyses were performed using the Kaplan-Meier estimation and competing-risks regression. Comparisons of any-cause RTOR rates were done using log-rank tests.

RESULTS

After exclusion criteria were applied, 419 subjects were analyzed. RTOR indications were organized into 5 categories. The overall rate for any RTOR by 3 years after surgery was 16.5%. Graft failure and contralateral ACL tear were the most common indications for RTOR, with predicted rates of 10.3% and 7.1%, respectively. ACL graft failure accounted for less than half of RTOR cases cataloged. Patients who had a concomitant meniscus procedure had lower rates of RTOR.

CONCLUSIONS

Approximately 1 in 6 pediatric ACLR patients underwent ≥1 repeat surgery within 3 postoperative years for indications ranging from wound breakdown to contralateral ACL rupture. While previous studies revealed high rates of complication after pediatric ACLR due primarily to graft failure, we found that re-tear is responsible for less than half of the 3-year RTOR risk. As almost half of re-tears in our sample occurred before clearance to return to full activities, we suspect that the high rate of complication is largely attributable to pediatric patients' high activity levels and difficulties adhering to postoperative restrictions. Early treatment of meniscus pathology may reduce rates of RTOR.

LEVEL OF EVIDENCE

Level III-therapeutic.

Utility of Perioperative Laboratory Tests in Pediatric Patients Undergoing Spinal Fusion for Scoliosis

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

We aimed to characterize the frequency of perioperative laboratory tests for posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) and to assess whether test results affected clinical management.

SUMMARY OF BACKGROUND DATA

Perioperative laboratory tests for PSF including complete blood count, coagulation laboratory tests, basic metabolic panels (BMPs), and type and screen, are commonly ordered based on providers' discretion or existing order sets. Studies have shown unnecessary laboratory tests as financially and physically costly in adults; however, no studies have examined the necessity of common perioperative laboratory tests in pediatric spinal deformity surgery.

METHODS

Retrospective review of patients aged 10-18 years who underwent PSF for AIS at our center in the past three years. The clinical utility of perioperative laboratory tests was assessed based on detected incidence of anemia, blood transfusions, hematology/endocrinology/nephrology consultations, insulin administration, and postponed/canceled surgeries.

RESULTS

A total of 234 patients were included (mean age 14.4 ± 1.8 years, 75% female). Of 105 (44.9%) patients with preoperative coagulation laboratory tests, 21 (20%) had abnormal results; however, none had subsequent hematology consultations or canceled/postponed surgeries. Postoperatively, only 5 (2.1%) patients and 30 (12.8%) patients had hemoglobin values less than 8 g/dL on postoperative day (POD) 1 and 2, respectively. Multivariate analysis identified POD1 hemoglobin ≤9.35 g/dL as the only predictor of hemoglobin <8 g/dL on POD2. Overall, there were 8 (3.4%) indicated blood transfusions postoperatively. Costs of unnecessary laboratory tests averaged $95.27 (range $49.72 to $240.27) per patient.

CONCLUSIONS

Many perioperative laboratory orders may be unnecessary in pediatric spinal deformity surgery, subjecting patients to extraneous costs and needlesticks. In particular, preoperative coagulation laboratory tests, perioperative BMPs, and additional postoperative CBCs for those with hemoglobin >9.35 on POD1 may not be warranted.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Comprehensive Wound Risk Stratification of Rib-Based Distraction Instrumentation Procedures

STUDY DESIGN

Single-center retrospective analysis of a prospectively collected registry.

OBJECTIVES

Identify factors predictive of rib-based distraction (RBD) instrumentation wound complication. Create a risk stratification model for RBD instrumentation wound complication.

SUMMARY OF BACKGROUND DATA

RBD instrumentation procedures have a high rate of wound complications, often requiring unplanned operative treatment. Currently, there is a relative lack of understanding of RBD complication risk factors compared with the comprehensive understanding of complication risk factors for other spine surgeries.

METHODS

Between January 2011 and September 2015, patients treated with RBD instrumentation at a single institution were analyzed for risk factors associated with surgical wound complications that resulted in unplanned operative treatment. Univariate logistic regression determined predictors of wound complication and multivariate regression determined independent predictive factors; α = 0.10.

RESULTS

A total of 122 patients aged 0-18 years underwent 140 implant surgeries in which 22 resulted in complications: 18 (82%) infectious and 4 (18%) noninfectious. Mean age at surgery was 5.2 years. Univariate analysis showed a correlation between wound complication rates and the following: male gender (p = .097), diapered patient with lower back incision (p = .004), bilateral procedure (p = .008), more than three incisions (p = .011), left iliac incision (p = .097), right iliac incision (p = .009), patient age ≤4 years (p = .10), and operative time >150 minutes (p = .079). Multivariate analysis identified the following independent predictors: age ≤ 4 years (p = .002), male gender (p = .04), number of skin incisions (p = .001), left iliac incision (p = .018), and nutritionally challenged (p = .044). The multivariate model predicted wound complications with an area under the receiver operating characteristic curve of 0.88.

CONCLUSIONS

Knowledge of risk factors for RBD instrumentation wound complications can be used to construct patient risk models. This can identify patients at higher risk for complications and influence clinical decision making.

LEVEL OF EVIDENCE

Level II.

Site-specific Surgical Site Infection Rates for Rib-based Distraction

BACKGROUND

Implantable rib-based distraction devices have revolutionized the treatment of children with early onset scoliosis and thoracic insufficiency syndrome. Unfortunately, the need for multiple skin incisions and repeated surgeries in a fragile patient population creates considerable infection risk. In order to assess rates of infection for different incision locations and potential risk factors, we generated a prospectively collected database of patients treated with rib-based distraction devices.

METHODS

We analyzed a cohort of patients with thoracic insufficiency syndrome from various etiologies that our institution treated with rib-based distraction devices from 2013 to 2016. Surgery type (implantation, expansion, revision/removal), and surgeon adjudicated surgical site infection (SSI) were collected. For this study, we developed a novel, rib-based distraction device surgical site labeling system in which incisions could be labeled as either proximal or distal surgical exposure areas. Treating surgeons documented the operative site, procedure, and SSI site in real-time.

RESULTS

A total of 166 unique patients underwent 670 procedures during the study period, producing 1537 evaluable surgical sites; 1299 proximal and 238 distal. Patients were 6.81±4.0 years of age on average. Forty-seven procedures documented SSIs (7.0%), while 40 (24.1%) patients experienced an infection. Analysis showed significant variation in the rate of infection between implantation, and expansion, and revision procedures, with implantation procedures having the highest infection rate at 13.1% (P<0.01). Infections occurred more frequently at distal sites than proximal ones (P=0.02).

CONCLUSIONS

Our novel, surgeon-entered, prospective quality improvement database has identified distal surgical sites as being at higher risk for SSI than proximal ones. Further, rib-based distraction device implantation procedures were identified as being at a greater risk for SSI than expansion or revision procedures. We believe this data can lead to improved prevention measures, anticipatory guidance, and patient care.

LEVEL OF EVIDENCE

Level II-prognostic study.

Releasing the tether: Weight normalization following corrective spinal fusion in cerebral palsy

PURPOSE

Feeding difficulties are common among patients with cerebral palsy (CP) and neuromuscular (NM) scoliosis. We theorize that posterior spinal fusion (PSF) reduces intra-abdominal pressure, resulting in improved feeding and subsequent weight gain. We hypothesized that, among nonambulatory patients with CP and NM scoliosis, we would observe significant gain in weight following PSF.

METHODS

Fifty subjects with nonambulatory CP who underwent PSF for NM scoliosis were included. Age and weight were recorded for the preoperative year; on the day of surgery; and at 6-month, 1-year, and 2-year follow-up. Weights were converted to weight percentiles using CP-specific growth charts. The weight percentile distributions were compared between time points using descriptive statistics as well as regression analysis.

RESULTS

The average change in weight from the day of surgery to 2-year follow-up was +3.4 percentiles. Patients who started out under the 50th percentile gained an average of 17.3 percentiles in the first year after PSF ( p = 0.009). Regression analysis showed that patients with baseline weight <50th percentile tended to gain in weight percentile over the first postoperative year ( β = 1.990, p = 0.001). No trend was present among this group prior to surgery ( p = 0.692) or during the second postoperative year ( p = 0.945). No trends were noted prior to or after surgery for patients with baseline weights ≥50th percentile. No significant association was observed between curve severity (measured by preoperative Cobb angle) and weight change.

CONCLUSIONS

This series is the first to document significant weight gain after PSF for NM scoliosis, supporting the theory that spinal correction improves digestive function.

LEVEL OF EVIDENCE

Prognostic level II.

The 22q11.2 deletion syndrome as a model for idiopathic scoliosis - A hypothesis

Adolescent idiopathic scoliosis (AIS), defined as a lateral deviation of the spine of at least ten degrees, is a classic enigma in orthopaedics and affects 1-4% of the general population. Despite (over) a century of intensive research, the etiology is still largely unknown. One of the major problems in all existing AIS research is the fact that most patients come to medical attention after onset of the curve. Therefore, it is impossible to know whether current investigated parameters are causative, or an effect of the scoliosis. Moreover, up until now there is no known animal model that captures the core features of AIS. In order to identify causal pathways leading to AIS we propose another approach, which has been of great value in other medical disciplines: To use a subset of the population, with a higher risk for a certain disease as a "model" for the general population. Such a "model" may allow the identification of causative mechanisms that might be applicable to the general population. The 22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion syndrome and occurs in ∼1:3000-6000 children and 1:1000 pregnancies. Nearly half of the population of patients with 22q11.2DS develop a scoliosis that in most cases resembles AIS as far as age at onset and curve pattern. We postulate that within 22q11.2DS certain causal pathways leading to scoliosis can be identified and that these are applicable to the general population.